Reducing oral frailty improves functional independence in older Brazilians: a causal inference study of...

Poor oral health is associated with functional decline and mortality in older adults, yet causal evidence linking oral health improvement with functional independence remains limited. We simulated the effects of hypothetical reductions in oral frailty on the cumulative probability of being alive and independent in basic activities of daily living (ADLs) among older adults in Brazil.

Data from the EpiFloripa Aging Cohort Study of community-dwelling adults aged 60 years or older in Florianópolis, Brazil, followed from 2009 to 2023, were analyzed (1702 participants). Oral frailty was measured at waves 1-3 using a seven-item composite score (range 0-7). The primary outcome was the cumulative probability of being alive and ADL-independent through wave 5, estimated using a discrete-time survival model. Longitudinal modified treatment policies with targeted maximum-likelihood estimation simulated nine oral health improvement scenarios, accounting for time-varying confounding and censoring.

336 deaths occurred during follow-up. A stepwise reduction in oral frailty increased the probability of being alive and ADL independent by 73% (probability ratio 1.73, 95% CI 1.48-2.02), corresponding to 15 829 additional functionally independent older adults per 100 000 individuals. Preventing edentulism with preserved masticatory function also improved the probability of being alive and ADL independent (probability ratio 1.21, 95% CI 1.08-1.36). Effects on survival alone were smaller and less certain.

Reducing oral frailty and preserving masticatory function increases functional independence among older adults, with smaller and uncertain effects on survival. Oral health is a modifiable determinant of healthy ageing.